2005-12-01  Jeff Johnston  <jjohnstn@redhat.com>

	* frame.c (backtrace_past_zero_pc): New static variable.
	(get_prev_frame): Don't return NULL for zero pc value if
	backtrace past-zero-frame option is turned on.
	(_initialize_frame): Initialize new command to allow backtracing
	past a zero pc value (set backtrace past-zero-pc).

testsuite/gdb.base:
2005-12-01  Jeff Johnston  <jjohnstn@redhat.com>

	* setshow.exp: Add testing of "set backtrace past-zero-pc" option.

Index: gdb-6.5/gdb/testsuite/gdb.base/setshow.exp
===================================================================
--- gdb-6.5.orig/gdb/testsuite/gdb.base/setshow.exp	2006-07-11 02:46:50.000000000 -0300
+++ gdb-6.5/gdb/testsuite/gdb.base/setshow.exp	2006-07-11 02:47:24.000000000 -0300
@@ -1,4 +1,4 @@
-# Copyright 1992, 1994, 1996, 1997, 1998, 2001, 2003
+# Copyright 1992, 1994, 1996, 1997, 1998, 2001, 2003, 2005
 # Free Software Foundation, Inc.
 
 # This program is free software; you can redistribute it and/or modify
@@ -106,6 +106,16 @@ if { ![target_info exists use_gdb_stub] 
     delete_breakpoints
     gdb_test "run" "Starting program:.*foo bar blup baz bubble.*" "passing args"
 }
+#test show backtrace past-zero-pc
+gdb_test "show backtrace past-zero-pc" "Whether backtraces should continue past a zero pc value is off." "default show backtrace past-zero-pc (off)"
+#test set backtrace past-zero-pc on
+gdb_test "set backtrace past-zero-pc on" "" "set backtrace past-zero-pc on"
+#test show backtrace past-zero-pc
+gdb_test "show backtrace past-zero-pc" "Whether backtraces should continue past a zero pc value is on." "show backtrace past-zero-pc (on)"
+#test set backtrace past-zero-pc off
+gdb_test "set backtrace past-zero-pc off" "" "set backtrace past-zero-pc off"
+#test show backtrace past-zero-pc
+gdb_test "show backtrace past-zero-pc" "Whether backtraces should continue past a zero pc value is off." "show backtrace past-zero-pc (off)"
 #test set check range on
 gdb_test "set check range on" "" "set check range on" 
 #test show check range on
Index: gdb-6.5/gdb/frame.c
===================================================================
--- gdb-6.5.orig/gdb/frame.c	2006-07-11 02:46:50.000000000 -0300
+++ gdb-6.5/gdb/frame.c	2006-07-11 02:51:20.000000000 -0300
@@ -131,6 +131,16 @@ Whether backtraces should continue past 
 		    value);
 }
 
+static int backtrace_past_zero_pc;
+static void
+show_backtrace_past_zero_pc (struct ui_file *file, int from_tty,
+			     struct cmd_list_element *c, const char *value)
+{
+  fprintf_filtered (file, _("\
+Whether backtraces should continue past a zero pc value is %s.\n"),
+		    value);
+}
+
 static int backtrace_past_entry;
 static void
 show_backtrace_past_entry (struct ui_file *file, int from_tty,
@@ -1313,9 +1323,7 @@ get_prev_frame (struct frame_info *this_
     }
 
   if (this_frame->level > 0
-#if 0
-      && backtrace_past_zero_pc
-#endif
+      && !backtrace_past_zero_pc
       && get_frame_type (this_frame) == NORMAL_FRAME
       && get_frame_type (get_next_frame (this_frame)) == NORMAL_FRAME
       && get_frame_pc (this_frame) == 0)
@@ -1629,6 +1637,17 @@ the rest of the stack trace."),
 			   &set_backtrace_cmdlist,
 			   &show_backtrace_cmdlist);
 
+  add_setshow_boolean_cmd ("past-zero-pc", class_obscure,
+ 			   &backtrace_past_zero_pc, _("\
+Set whether backtraces should continue past a zero pc value."), _("\
+Show whether backtraces should continue past a zero pc value."), _("\
+Normally GDB stops backtracing when it finds a zero pc.\n\
+Set this variable if you need to see the rest of the stack trace."), 
+ 			   NULL,
+			   show_backtrace_past_zero_pc,
+			   &set_backtrace_cmdlist,
+ 			   &show_backtrace_cmdlist);
+
   add_setshow_integer_cmd ("limit", class_obscure,
 			   &backtrace_limit, _("\
 Set an upper bound on the number of backtrace levels."), _("\